This invention relates to equipment mounting structures, and particularly to such structures including cabinets, racks, frames and the like for removably housing circuit board packages used for telecommunications purposes.
In telecommunication networks, changes are constantly occurring, both in the subscribers connected to the network and to the services provided to the various subscribers. For accommodating rapid changes, the recent practice has been to terminate subscriber communication lines, e.g., metal wires and optical fibers, on circuit board packages removably housed within equipment shelves. The shelves, in turn, are mounted on various mounting structures, referred to as racks or frames and the like, which, in turn, can be mounted within enclosed cabinets. The circuit board packages include various electrical and/or optical components for processing signals arriving at the circuit board packages, and the mounting structures provide means for housing the circuit board packages and include cables for routing signals and electrical power to, between and from the various circuit boards. Changes in the network are readily achieved by replacing various circuit board packages or changing the signal routing therebetween.
For greatest flexibility of use, design standards have been established whereby different circuit board package receiving shelves can be interchanged with one another in the same and different mounting structures located in a common telephone control office or different central offices. A problem caused is that the design standards are often so complete and detailed that desired changes in the various components of the mounting structures, arising from experience with use of the mounting structures or in the design of replacement structures, are difficult to make within the existing standards.
The present invention addresses this problem primarily in the context of providing improved components for use in existing mounting structures or, owing to advantages provided by the new components, for use in new mounting structures made according to new standards.
In general, mounting structures for which components are provided according to the present invention comprise a frame formed from a grid of support members, spaced apart shelf-assemblies mounted on the frame for receipt of circuit board packages, and various cables more or less fixed in place for conveying signals and power throughout the frame and any cabinet in which the frame is disposed.
In accordance with this invention, a mounting method makes use of a bracket comprising an elongated metal strip including spaced apart mounting lugs projecting transversely (e.g., at right angles) from the strip. The lugs include screw threaded openings. In the mounting method, the lugs are inserted through slots in side walls of the shelf-assemblies and screwed in place against an interior surface of the side walls by means of flat-headed screws passing through counter-bored openings through the side walls. The elongated metal strips project laterally outwardly from the side walls for the securing of the shelf-assemblies to the supporting framework. The internal securing of the lugs to the side walls avoids increases in the maximum allowed widths of the shelf-assemblies.